Semiconductor component manufacturers typically include structures for protecting their devices against failure caused by large transient electrical stimuli. When the stimulus is an electrostatic discharge (ESD) event, manufacturers generally incorporate protection structures that account for failure mechanisms attributed to the Human Body Model (HBM) and to the Charged Device Model (CDM). The Human Body Model simulates electrostatic discharge from a human body to a semiconductor device that is sensitive to the discharge event. Here, charge accumulated on the human body discharges to the semiconductor device. The Charged Device Model simulates the discharge of charge accumulated on the semiconductor device itself during the assembly process. When these charged devices contact metal objects, a discharge event occurs which is short in duration accompanied by peak currents capable of exceeding ten amperes.
To protect against these events, semiconductor component manufacturers incorporate primary and secondary clamping structures into their components. The primary clamping structures protect against high voltage discharge events associated with contact by humans or other charged materials. They are coupled to input and output pads of the semiconductor devices to prevent device failure due to positive and negative voltage excursions. The secondary clamping structures protect against the high currents generated by discharge events associated with the semiconductor component contacting metal objects. They also protect against damage caused by large positive and negative voltage excursions. These structures are coupled to the input and output bond pads through a resistor, which lowers the voltage created by the large transient current. In addition to being coupled between the input or output bond pads, the resistance couples the primary clamping structure to the secondary clamping structure. A drawback of including this resistor is that it has a fixed resistance value that must be kept low for use in high frequency or radio frequency applications. If the resistance value is too high, the Resistance-Capacitance (RC) time constant of the pin coupled to the bond pad makes the device unacceptably slow. However, when the resistance is too low, the voltage drop across the resistor is too low to provide adequate ESD protection for the semiconductor device.
Accordingly, what is needed is a semiconductor component having a protection structure and method capable of protecting against large transient electrical stimuli, wherein the protection structure and method include an element that does not degrade the high frequency performance of the semiconductor component while providing sufficient device protection.